<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div>
  <input type="text"  v-model="num1">
  <input type="text"  v-model="num2">
  <input type="button" value="加" @click="f(1)">
  <input type="button" value="减" @click="f(2)">
  <input type="button" value="乘" @click="f(3)">
  <input type="button" value="除" @click="f(4)">
  <h1>结果:{{info}}</h1>
</div>
<script src="js/vue.min.js"></script>
<script>
  let v = new Vue({
    el:"body>div",
    data:{
      info:"",
      num1:"",
      num2:""
    },
    methods:{
      f(x){
        if(isNaN(v.num1)||isNaN(v.num2)){
          v.info="输入错误";
          return;
        }
         switch (x){
           case 1:
             v.info = v.num1*1 + v.num2*1;
             break;
           case 2:
             v.info = v.num1 - v.num2;
             break;
           case 3:
             v.info = v.num1 * v.num2;
             break;
           case 4:
             v.info = v.num1 / v.num2;
             break;
         }
      }
    }
  })
</script>

</body>
</html>